Have You Experienced This?

I have no idea who it is, but I think I have a "stalker" online. They are constantly making new accounts and trying to add me on Facebook. They even have accounts that they'll use for a few weeks and add as many of my friends as they can, to make it seem more real. I'm pretty sure it's the same person. They have been doing this for a couple of years now. I thought they would've gotten bored by now. I have a suspect, though. I think it's a guy my friend used to work with.